Most Cancer-related Blood Clots Occur in Outpatients

In a study of nearly 18,000 people with cancer, University
of Rochester Medical Center researchers have found
that when blood clots develop – a well-known and serious
complication of cancer treatment – 78 percent of the time
they occur when a person is out of the hospital, at home or
elsewhere, while on chemotherapy.

This data is striking because, until now, outpatients have
not been systematically studied, and previous data gathered
on the incidence of blood clots was mostly from those hospitalized,
who tend to be sicker. However, with a shift toward
outpatient cancer treatment, future efforts to prevent blood
clots should focus on helping people to avoid complications
so they can continue to live fully, by working, raising
children, and exercising, during cancer care, says Alok
Khorana, MD, associate professor in the James P. Wilmot
Cancer Center at URMC.

Clots form most often in the legs,
lungs, or abdomen and are life-threatening if not treated.

“One in five patients develops blood clots after a cancer
diagnosis, and we believe that number is rising,” Dr. Khorana
says. “The Surgeon General recently issued a Call to
Action to reduce venous thromboembolism. At this point,
public health efforts have focused on inpatient prophylaxis.
These new data suggest that to reduce the burden of VTE
in cancer patients, prevention efforts will have to shift to
the outpatient arena as well.”

The medical term venous thromboembolism is a mass of
red blood cells, clotting proteins, and platelets that block the
normal flow of blood. Clots form most often in the legs,
lungs, or abdomen and are life-threatening if not treated.

People with cancer are more prone to blood clots for many
reasons: the malignancy itself can secrete proteins associated
with blood clots; several treatments (including surgery,
chemotherapy, and hormonal therapy) raise the clot risk;
decreased mobility due to active disease or hospitalization;
a genetic predisposition; or having other health problems,
such as infections, obesity, anemia, and lung disorders. And
once a blood clot occurs, a person with cancer is much more
likely to have other clots later.

“Ongoing public health issues that we must address are
how to educate patients on the importance of blood clot prevention
and improving compliance to preventive treatment,”
Dr. Khorana says. People with cancer should immediately
report to their physicians any unusual symptoms, such as
swelling or redness in limbs or shortness of breath, even if
they are otherwise feeling well.

The Rochester group published a risk model in the journal
Blood, and based partly on research from the group, the American
Society of Clinical Oncology, in 2007, issued its first set
of guidelines for clinicians for the prevention of blood clots in
people with cancer.

♦ ♦ ♦ ♦ ♦

This article was published in Coping® with Cancer magazine,
January/February
2012.